An interesting view on how 'green' CFLs really are:

Yes, but probably not for at least another 5 years.

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I think he overplays the failure rate somewhat. 10000 hours continuous running is a lot more elapsed time than 1 year for a normal use. The only CFLs I have had to replace to date failed by mechanical damage not end of life. The longest running ones are now at 6 years elapsed so their output is beginign to dip a bit.

However, I do agree that because they contain a trace of mercury they should not be in the general tip crushed waste stream but should go the way of other small electrical goods and batteries.

You think gallium arsenide and its relatives will be better...less mobile, plastic encased I suppose but still pretty toxic stuff.

Regards, Martin Brown

** Posted from **

The guy contradicts himself. He says that the mercury vapour escapes from the garbage truck before it gets to the landfill, and then he says it's locally dangerous, unlike power plant mercury.

Once the vapour is in the air, it's very unlikely to wind up anywhere but the ocean. 100 million CFLs per year is something like 1000 pounds of mercury, spread out over the Earth.

It's a nit, folks.

Cheers,

Phil Hobbs

On a sunny day (Mon, 28 Jul 2008 08:37:44 -0400) it happened Phil Hobbs wrote in :

Well, garbage trucks wil ldrive a lot before they are full and go to a landfil.

Plus 100 million little PCBs with all sorts of chemicals.

I am not sure, it is an interesting viewpoint at least.

Let me lay it out a little clearer, then.

The abundance of mercury in crustal rocks is about 67 ppb and in seawater 50 ppt.

So 500 kg of mercury is equivalent to the natural background abundance in

500 kg/(6.7x10**-8) = 7x10*12 kg of country rock

or

500 kg/(5x10^-11) = 1 x 10**16 kg of seawater.

Sounds like a lot. One cubic metre of water weighs 1000 kg, so 100 million CFLs per year is equivalent to the mercury contained in

10**16/1000 or 10**13 cubic metres, or 10**4 cubic kilometres--a cube 21.5 km on a side. Sounds like really a lot, but the ocean's volume is about 1.3 billion cubic km. So if you dumped all that mercury into the ocean and stirred, you'd increase the mercury content of seawater by

100%*10**4/(1.3*10^^9) or 0.0008% per year--and that's 0.0008% of a barely-measureable 50 ppt to begin with.

For country rock, the picture is even clearer. That 7x10**12 kg of crust has a specific gravity of about 3.5 for rock, so let's be generous and say that soil is half rock and half organic matter. (I wish my garden was that good, but that's another story.)

So figure 1.7*10**3 kg / m**3 of rock for topsoil. That 1000 kg Hg is then equivalent to the quantity of naturally-occurring mercury in

7*10**12 kg / 1000 kg/m**3 or 4.4 x 10**9 cubic metres of soil, or a square 66 km on a side by 1m deep. That's a big area, of course, but the surface area of the USA alone is 10 million square km. So again, if it's evenly distributed, all that mercury doesn't do squat.

So we can ignore mercury in the atmosphere, and we're left with concentrations in certain areas.

There's no doubt that mercury pollution in Minamata Bay led to high mercury concentrations in the food chain and consequently to a horrible tragedy. That's data. Minamata fish had over 10 ppm (!) methyl mercury at the time of the tragedy, but it got down to below 300 ppb by 1997, so the Japanese government reopened the fishery.

And the total mercury effluent at Minamata was about 200 tons (i.e. 400 years' production of CFLs at 100 million per year), just dumped in one little bay.

And that was methyl mercury, one of the most dangerous forms (due to easy uptake by fish).

They dredged it all up and made an island out of it--a form of containment far less effective than a clay-lined landfill. Yet 50 years on, the fish in the bay are safe to eat--right next to that nasty landfill with the hundreds of tons of mercury in it.

So mercury is dangerous, all right, but the actual level of risk to anyone from CFLs is pretty small.

As I said, it's a nit.

Cheers,

Phil Hobbs

Let me lay it out a little clearer, then.

The abundance of mercury in crustal rocks is about 67 ppb and in seawater 50 ppt.

So 500 kg of mercury is equivalent to the natural background abundance in

500 kg/(6.7x10**-8) = 7x10*12 kg of country rock

or

500 kg/(5x10^-11) = 1 x 10**16 kg of seawater.

Sounds like a lot. One cubic metre of water weighs 1000 kg, so 100 million CFLs per year is equivalent to the mercury contained in

10**16/1000 or 10**13 cubic metres, or 10**4 cubic kilometres--a cube 21.5 km on a side. Sounds like really a lot, but the ocean's volume is about 1.3 billion cubic km. So if you dumped all that mercury into the ocean and stirred, you'd increase the mercury content of seawater by

100%*10**4/(1.3*10^^9) or 0.0008% per year--and that's 0.0008% of a barely-measureable 50 ppt to begin with.

For country rock, the picture is even clearer. That 7x10**12 kg of crust has a specific gravity of about 3.5 for rock, so let's be generous and say that soil is half rock and half organic matter. (I wish my garden was that good, but that's another story.)

So figure 1.7*10**3 kg / m**3 of rock for topsoil. That 1000 kg Hg is then equivalent to the quantity of naturally-occurring mercury in

7*10**12 kg / 1000 kg/m**3 or 4.4 x 10**9 cubic metres of soil, or a square 66 km on a side by 1m deep. That's a big area, of course, but the surface area of the USA alone is 10 million square km. So again, if it's evenly distributed, all that mercury doesn't do squat.

So we can ignore mercury in the atmosphere, and we're left with concentrations in certain areas.

There's no doubt that mercury pollution in Minamata Bay led to high mercury concentrations in the food chain and consequently to a horrible tragedy. That's data. Minamata fish had over 10 ppm (!) methyl mercury at the time of the tragedy, but it got down to below 300 ppb by 1997, so the Japanese government reopened the fishery.

And the total mercury effluent at Minamata was about 200 tons (i.e. 400 years' production of CFLs at 100 million per year), just dumped in one little bay.

And that was methyl mercury, one of the most dangerous forms (due to easy uptake by fish).

They dredged it all up and made an island out of it--a form of containment far less effective than a clay-lined landfill. Yet 50 years on, the fish in the bay are safe to eat--right next to that nasty landfill with the hundreds of tons of mercury in it.

So mercury is dangerous, all right, but the actual level of risk to anyone from CFLs is pretty small.

As I said, it's a nit.

Cheers,

Phil Hobbs

I think he overplays the failure rate somewhat. 10000 hours continuous running is a lot more elapsed time than 1 year of normal use. The only CFLs I have had to replace to date failed by mechanical damage not end of life. The longest running ones are now at 6 years elapsed so their output is begining to dip a bit.

However, I do agree that because they contain a trace of mercury they should not be put in the general tip crushed waste stream but should go the way of other small electrical goods and batteries. The amounts of mercury involved are really very small though but it is essential to their operation.

You think gallium arsenide and its relatives will be better...less mobile, plastic encased I suppose but still pretty toxic stuff.

Regards, Martin Brown

On a sunny day (Mon, 28 Jul 2008 10:06:45 -0400) it happened Phil Hobbs wrote in :

That is a lot of impressive figures Phil, sorry to hear about your garden. Apart from the mercury, that person says 'better magnetic ballasts then electronics' I have 2 18W fluorescent with magnetic ballast right over my desk. The ballasts (armature) I bought around 1983 IIR. The CFLs I buy seem to break down on a regular basis, the one in the kitchen went out some weeks ago, it is only on in the evening, think it did not make 10000 hours... So the amount of electronics junk could be reduced with magnetic ballasts, Or is there an argument against that too?

Cool:

"They found no change in methylmercury levels in the tuna over that

27-year period.

The researchers predicted that mercury in the surface waters should have increased by up to 26 percent during this time, according to a computer model. The model took account of the change in atmospheric mercury, the sub-equatorial Pacific waters and the potential for mixing in the"thermocline" ? a transition layer in the ocean where temperature changes rapidly."

Ya gotta love those computer models.

John

When we bought our house, the composition of our back yard was

23% rocks

41% clay

32% construction debris

4% ants.

John

For another 50 cents or so, the electronic ballasts could be made reliable.

Why have an input electrolytic at all? Why not full-wave rectify and let the light be modulated at 120 Hz? Make it triac dimmable while you're in there.

John

Ultimately I think it's going to be condoms, pills and abstinence, or mass starvation.

Between the right wingers with their heads in the sand and the left wingers with their heads up their donkeys (I never did get that aphorism :) I doubt that you'll ever see a rational policy to deal with the fact that there's too damn many of us living too damn high on the hog.

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http://www.wescottdesign.com

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On a sunny day (Mon, 28 Jul 2008 08:27:07 -0700) it happened John Larkin wrote in :

50 cents is a lot on a 1$ bulb ;-)

You could try it, not sure it would have no side effects, few kHz modulated at 120Hz, sidebands, dunno :-)

>

desk.

It'll drive you crazy. There isn't enough of a lowpass effect downstream from there (in the glass tube).

Yes! I am still surprised that there haven't been more damages from people screwing a CFL into a lamp that happens to be on a dimmer. Joe Sixpack usually doesn't have a clue about those limitations and may not always read the text on the package.

--
Regards, Joerg

http://www.analogconsultants.com/

"gmail" domain blocked because of excessive spam.
Use another domain or send PM.

And now they want to impose a CO2 trading scheme "upstream from the consumer" based on computer models. Great. Was reported in the Sacramento Bee last week. Guess who's going to pay the piper?

It all leads to the same thing, more bureaucrats, more taxes, less productivity.

--
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Use another domain or send PM.

desk.

No different from a traditional ballast.

The RiteAid up the block is selling dimmable, high power-factor CFLs now. When something sells in the billions, a smart control IC isn't unreasonable.

As long as the legal types are passing laws about saving the planet, they could mandate that actual lifetimes be posted on the gadgets, not "up to 10,000 hours." Or mandate real lifetime standards. 99 cent crap CFL sometimes fail in the first minute of operation. I replaced one recently and didn't make it to the bottom of the ladder when the replacement blew up.

John

Let me muddy the waters a bit...

The State of Maine did an extensive study on the safe handling and disposal of CCFL lamps.

Note that you can inhale a rather toxic dose of mercury vapor if you break one open in a badly ventilated room, especially near floor level.

My personal experience with CCFL's is mixed. I buy nothing but the cheapest (from Costco) which tend to last about a year or two. CCFL's that I purchased perhaps 5 years ago are still running, but are running at substantially reduced output. The bathroom CCFL's seem to be the worst, blowing up at an estimated 800 hours, probably from water condensing on the PCB inside. Those mounted upside down (FL coil pointed downward) seem to last only about 1200 hours. Those mounted vertically (FL coil pointed upward) seem to last much longer at perhaps 3000 to 5000 hours.

Disposal is also a problem. CCFL's are treated as hazardous household waste. They can be dropped off for free in Santa Cruz county, but only 2 days per week.

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Jan Panteltje wrote in news:g6k36a$8t4$1 @aioe.org:

Personally/IMO:

CFLs were and are an interim measure, IMO. I've had some CFLs that have lasted for more than 6 years; and I've had others that blew out after only several months. I've read that part of prolonging a CFL's service life is to leave it on for about 15 min after turning it on.

Once consideration with CFLs is that they put off a lot less heat than do incandescents. I've had pet birds for at least 25 years, and have been using CFLs for at least that long, one reason being that, if the bird takes off and ends up plopping down onto a lamp, the CFLs are far elss likely to cause burns. If I had kids, I'd be equally concerned.

But they do also reduce one's electric bill, there's no doubt about that.

Also, in a hot climate, the most expensive thing is probably air conditioning, so using CFLs contributes less to straining the AC than did/do incandescents. I've been looking at household LEDs, tho' (not just LEDs for my solar art lamp idea) and will start switching over, because they don't have the murcury problem as do CFLs.

The Democrats will base a tax on those computer models ;-)

Turns out that Obama's "the rich" is anything over $108K/year.

...Jim Thompson

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